#include <stdint.h>
int main()
{
	//1.时钟配置 RCC_APB2ENR 0000 0000 0000 0000 0100
	*(uint32_t *)(0x40021000 + 0x18) = 4;
	
	//2.GPIO工作模式配置 GPIOx_CRL 0000 0000 0000 0011
	*(uint32_t *)(0x40010800 + 0x00) = 3;
	
	//3.PA0输出低电平 GPIOx_ODR 1111 1111 1111 1110
	*(uint32_t *)(0x40010800 + 0x0C) = 0xfffe;
	
	//4.死循环保持状态
	while(1)
	{
	}
}
